The present invention relates to an electrophotographic image forming system.
Generally, upon receipt of a printed data, the electrophotographic image forming system converts it into an image data and applies such luminous flux as laser beam to a photoconductor to form an image by electric charge, which is a so-called latent image. Then colored particles (toner) are deposited thereon on an selective basis by a development device, and latent image is formed into an manifest image, on the one hand. On the other hand, a medium such as form is fed to the photoconductor by a feed means such as a roller, and the image formed on the photoconductor is transferred to the medium. Then the image is fused onto the form by a fusing device, thereby completing printing. In such an electrophotographic image forming system, a form to guarantee print quality is normally specified to ensure stable printing operation. Therefore, the user is required to get a form specified for each system. There is no problem if such a form can be easily obtained. If not, the user has to be prepared for poor print quality. In addition to poor print quality, jamming occurs where the form is wound on the drum, depending on the case. Therefore, when other than specified forms are used, printing operation is performed by supplying the form from the manual feed tray to ensure that the form feed path will be shaped in a straight line wherever possible. However, this method cannot solve the problem of the drum wound by paper as described above. Even if the specified form is used, the form does not always exhibit predictable behavior when changes in form storage conditions and surrounding environment are taken into account. The form fed at a high speed may give vibration to parts inside the form feed path or may contact them by instantaneous behavior, causing the unfused image to be disturbed. Furthermore, paper used for printing includes a great variety of forms such as plain paper which is also called a copy form, OHP form, label form, envelope and post card. They may be used on the electrophotographic image forming system. The media greatly differing in the thickness, rigidity and the degree of curling of the form may be used. Thus, the system is required to cope with a great variety of forms.
The object of the present invention is to provide an electrophotographic image forming system characterized by a mechanism of stabilizing the behavior of the tip of the form when the form with unfused colored particles (toner) deposited thereon is fed to the fusing device.
To achieve the above object, the present invention has a form posture correcting protrusion provided on the non-printing area of the surface of the form with unfused colored particles (toner) deposited thereon inside the feed path of the form with unfused colored particles (toner) deposited thereon, so that form behavior can be controlled when the form is fed to the fusing device.